The present invention relates to secondary mirror tilting devices and, more particularly, to devices for tilting the secondary mirror of a reflecting telescope which include a compensating plate and electromagnetic drive means for oscillating the mirror and the compensating plate in synchronism.
The periodic tilting or oscillation of the secondary mirror of a reflecting astronomical telescope makes it possible to reduce the effect of the background radiation of the earth's atmosphere and of the telescope components during photometric measurements as a result of the fact that the radiation from closely adjacent fields of the sky is measured differently. Preferably the secondary mirror tilting device of a reflecting telescope must operate in a vibrationless manner and should consume as little power as possible. This is especially true when the reflecting telescope is to be used for measurements in the infrared region of the spectrum and, for this purpose, must be cooled to very low temperatures such as 10.degree. K. and when the telescope is intended for use in space. Heretofore, tilting or oscillating systems for the secondary mirror of a reflecting telescope have required more power than is desirable.
Accordingly, it is an object of the present invention to provide an angular momentum-compensated secondary mirror tilting device for a reflecting telescope, particularly for a cooled reflecting telescope to be operated in space, which consumes a miminum of power.